If the headgasket in a car has been fixed, will the oil dipstick look like chocolate milkshake?

I inspected a car today ( Renault Clio 1.2 1999) The owner said that he fixed that headgasket but when I checked the oil dipstick it has rusty look and there is barely black colour of oil there. He claimed that will take time for it to get to its original colour. However, I wasn't convinced but since I'm no mechanic I couldn't argue that either. Any idea? Thanks in advance.